e23072 Background: Interactions between chemokines and their receptors can regulate anti-tumor response by influencing the migration of immune cells. Atypical Chemokine Receptor 1 (ACKR1/DARC), a genetically diverse transmembrane GPCR, acts as a decoy receptor for a variety of CXC and CC chemokines, including those with pro-malignant and pro-inflammatory effects, such as CCL2 and CXCL8 . The purpose of this study is to determine if the migration of tumor-associated immune cells is unique based on epithelial ACKR1 expression on breast cancer cells, and if this association is correlated to an increase in pro-malignant chemokines, survival, or race. Methods: Immunohistochemistry techniques were used to determine expression of ACKR1 on primary breast tumors, along with T-cells, B-cells, dendritic cells, and macrophages. Concentrations of pro-inflammatory chemokines in circulation were determined using a Luminex-based immunoassay. In silco analyses were performed to determine associations between ACKR1 tumor status, race, and survival. Finally, using human breast cancer cell lines and immunofluorescence techniques, co-localization between ACKR1 and pro-inflammatory chemokines was investigated. Results: Results from these tests indicate that there is differential infiltration of immune cell types in tumors expressing ACKR1, , which were not detected in ACKR1 negative tumors. Significantly increased circulating CCL2 and CXCL8 chemokine levels we also determined to be positively correlated with ACKR1 expression in primary breast tumors. Survival analyses showed a significantly increased relapse free survival in patients having tumors with high ACKR1 expression, while investigations into racial differences revealed a significant race effect, with Caucasians having higher ACKR1 levels on their tumors than African-Americans. Finally, co-localization between ACKR1 with CCL2 and CXCL8 is observed in cultured human breast cancer cells. Conclusions: tumors positively expressing ACKR1 to have a more favorable prognosis suggest that a role of ACKR1 on breast tumor cells is to sequester pro-inflammatory chemokines in the tumor microenvironment, recruiting a distinct subset of tumor-associated immune cells.
Interleukin 6 secreted from adipose stromal cells promotes migration and invasion of breast cancer cells
